The broad, long-term objective is to develop a low cost, easy to use system that can convert diagnostic MRI scanner into a functional neurosurgical MRI suite. The specific aims of the project are: 1. Develop the display-only mode of the HMD that integrates MRI realtime scans and device tracking annotation into a stereoscopic 3D display. Feasibility of such HMD has been demonstrated in Phase I of the project. 2. Develop a hybrid image-based and gradient-tracking based head positioning system for the augmented reality system to provide head position in the MRI coordinate system at the edge area of the scanner. 3. Develop the augmented reality mode of the HMD that presents 3D anatomic data from previously acquired MRI onto neurosurgical operation field at the edge of the scanner. 4. Develop application specific MRI protocols that provide non-distorted high-resolution 3D rendered images with multiple contrast characteristics (e.g. T1, T2, FLAIR, MP-RAGE, etc.); and the planning and visualization software interface to incorporate these images to procedure planning and guidance using augmented reality. 5. Conduct phantom tests to demonstrate adequate operation of the HMD in its two modes of operation. 6. Conduct animal tests to evaluate the HMD in conducting percutaneous interventions and open neurosurgical procedures. The proposed project complies with two of the four specific goals of PA-10-079, namely: - The development and optimization of fully integrated cancer imaging, monitoring, and therapy systems. - Partnerships among small business and academic clinical centers in order to reach the research goals. The development of the technology and the eventual product for clinical use will be done jointly by Robin Medical, Inc., a small business specializes in the development of navigation systems for MRI; and the Magnetic Resonance Research Center (MRRC) at the University of Maryland, Baltimore, having extensive experience in human and large animal research in MRI and development of customized scan sequences. Robin Medical will develop a head mounted display (HMD) and head mounted augmented reality system (HMARS), based on feasibility demonstration in Phase I. The HMD will provide a 3D display of realtime or previously acquired MR images along with realtime tracking annotation. The HMARS will provide an augmented reality display composed of view of the surgical field obtained by head mounted cameras, MR images, and tracking annotation. The MRRC group will develop customized MRI sequences for real-time guidance and display of 3D rendered structures and will conduct the technical and animal experimentation with the system.